The present invention relates generally to a multi-stage centrifugal pump assembly with at least two impellers, for example an at least two-stage centrifugal pump.
With such multi-stage centrifugal pump assemblies, several impellers are arranged one after the other in the delivery direction, so that a further pressure increase takes place from stage to stage. A problem with these centrifugal pump assemblies is that they firstly need to be bled and filled with fluid on starting operation. The centrifugal pump assemblies are not self-priming. This is disadvantageous with certain case of application, for example in fire extinguishing devices, with which a constant filling with fluid, in particular water cannot be ensured. It is important for the applied pumps to be self-priming in such devices.